More than 400 people infected with COVID-19 were mistakenly told by St Vincent’s Hospital in Sydney that they had tested negative to the virus.

In a statement released on Sunday, the hospital apologised for the mistake and said its laboratory, SydPath, had begun contacting those affected immediately after becoming aware of the mistake on Sunday morning.

The hospital said it believed the false negatives were due to “human error”, but it has set up an emergency response team to investigate the cause of the mistake.

SydPath medical director Anthony Dodds gave a press conference on Sunday afternoon but took no questions from the media.

“Owing to the very large volume of tests that we’ve been contending with at SydPath, last night we incorrectly messaged 400 patients who had been swabbed at our centres on December the 22nd and December the 23rd, advising them that they had tested negative to COVID,” Professor Dodds said.

“These people, in fact, had tested positive to COVID.”

Professor Dodds said none of the sailors involved in the Sydney to Hobart boat race were believed to be in the cohort of affected people.

“We sincerely apologise for the mistake that has been made,” he said.

‘We’re all going to get Omicron’

The news came hours after New South Wales reported a record 6394 new cases.

The state’s health minister, Brad Hazzard, later told reporters that everyone in NSW should expect to catch Omicron.

“We would expect that pretty well everybody in NSW at some point will get Omicron … and if we’re all going to get Omicron, the best way to face it is when we have full vaccinations including our booster,” he said.

Mr Hazzard added that residents should “think carefully” before calling an ambulance, as 2000 health workers had been furloughed due to isolation requirements and the health system was now under “enormous pressure”.

“The challenge for us in the state is to make sure that our health system can cope with that oncoming virus that is so transmissible,” he said.

Elsewhere on Sunday, Victoria reported 1608 new cases and two further deaths; Queensland reported 714 cases; South Australia reported 774; and the ACT reported 71.

Stricter rules in SA

In response to the surging case numbers, the South Australian government delayed plans to further ease restrictions and instead brought back limits on family gatherings and hospitality and gym capacities.

From midnight, indoor dining will be restricted to one person per four square metres and outdoor dining to one person per two square metres.

Limits on family gatherings will also be reduced from 30 to 10 people, and gyms will be allowed no more than one person per seven square metres.

Meanwhile, interstate travellers will no longer need to take a PCR test before arriving, but have been advised to take a rapid antigen test after entering the state.

SA Premier Steven Marshall said the new restrictions were needed to ensure the Omicron wave did not overwhelm the state’s health system.

“We are increasingly concerned about the new Omicron variant,” Mr Marshall said.

“If we don’t take decisive action now, we could see South Australia in the thousands [of daily cases] within the next couple of weeks.

“We’re sending a very strong message to all South Australians now: please, reduce your mobility, reduce the number of people you interact with.”